STDOUBT
Veteran Member
The one time I've de-gunked an IM I scraped every hole out best I could with china grade butter knives, into a trash bag-lined box. Then soaked the bugger in ~5 gallon bucket of Awesome(tm) degreaser for a week. Then took a few varied sized bottle brushes and went at it deep as possible, more rinsing with the degreaser and all nice and shiny.